This application claims benefit of Japanese Application No. 2000-202544 filed in Japan on Jul. 4, 2000, the contents of which are incorporated by this reference.
1. Field of the Invention
The present invention relates to an endoscope having a soft insertion member and capable of being sterilized with high-temperature high-pressure steam.
2. Description of the Related Art
An endoscope having a soft insertion member is inserted into a tortuous body cavity, whereby endoscopic examination may be carried out or a therapeutic instrument may be, if required, used to perform a cure. Endoscopes are therefore widely used in various fields including the medical field.
For example, Japanese Unexamined Patent Application Publication No. 2-283346 describes an art relating to such an endoscope. Herein, a flexible tube that is an integral part of an insertion member of the endoscope has a two-ply sheathing made of a high polymer material. Consequently, excellent inserting smoothness is ensured and improved durability is offered.
A recent trend is not to use ethylene oxide to sterilize an endoscope from the viewpoint of being friendly to the environment. Therefore, a high-temperature high-pressure steam sterilizer that employs harmless high-temperature high-pressure steam instead of ethylene oxide is sometimes used to sterilize an endoscope.
When such a high-temperature high-pressure steam sterilizer is used to sterilize an endoscope, the endoscope is first stowed in a sterilization case and then sterilized.
However, as mentioned above, when an endoscope is stowed in a sterilization case and then sterilized, the soft insertion member of the endoscope is exposed to high-temperature high-pressure steam while being settled in a tray, which is placed in the case, in a specific shape. A thermal load is applied to the insertion member in the case where tortuousness for a resin used in the insertion member occurs. Consequently, the insertion member may be deformed in the specific shape, which is defined by the tray, at the room temperature after completion of sterilization. This may affect inserting smoothness and maneuverability.
Accordingly, an object of the present invention is to provide an endoscope that is bent by a small magnitude at room temperature after completion of sterilization with high-temperature high-pressure steam. The endoscope can therefore offer improved inserting smoothness and maneuverability.
Briefly, according to the present invention, there is provided an endoscope having a soft insertion member. The insertion member consists mainly of a flexible tube whose sheathing layer is made of a resin and one or more built-in components incorporated in the flexible tube. At least one of the built-in components deforms by an extent smaller than an extent by which the flexible tube deforms, at room temperature, after being subjected to a high-temperature high-pressure steam sterilization (which includes a high temperature load) that is performed with the insertion member settled in a specific shape.